Her son Dan suffered from terminal cancer and the former nurse claims medicinal cannabis was the only way to relieve his nausea and pain.

Lucy Haslam explains her plan for an amnesty for patients using medicinal marijuana to the ABC's Fran Kelly. (Post continues after video.)

After his death, Haslam founded United in Compassionand has consistently lobbied the NSW state government for a more compassionate approach.

Hence, she started a petition on change.org, using Lambert's story to illustrate the need to legalise medical cannabis.

Haslam is advocating to replace the existing Terminal Illness Cannabis Scheme with what she has labelled the Compassionate Access Cannabis Scheme.

"I believe that compassionate access to medicinal cannabis is important, because despite the war on drugs and the long history of propaganda around cannabis, many very sick patients find that it is a great source of relief for many severe and debilitating symptoms," she told Mamamia.

"Unbiased research is supporting the therapeutic benefits of cannabis and slowly attitudes are changing, but patients that are needing medicinal cannabis urgently, cannot afford to wait for the slow clinical trial validation process and are forced to become criminals just to manage their symptoms.

"It is a human rights issue that requires compassion and common sense."